Cap rock refers to the rock that caps a reservoir thereby keeping the reservoir fluids contained in the reservoir and preventing their leakage out. Reservoir engineers are interested in maintaining the integrity of the cap rock to insure that production of the reservoir fluids can be controlled. Unfortunately, excessive extremes in stresses, pore pressure or temperature can fracture cap rock. Hence, reservoir engineers want to know the potential for fracturing cap rock in order to properly plan production parameters for producing the reservoir fluids. For example, proper Steam Assisted Gravity Drainage (SAGD) planning requires setting limits to the operational parameters (such as temperature and pressure of steam, duration of steam injection, etc.) so that the cap rock remains intact by avoiding the formation of cap rock fractures. Hence, it would be well received in the oil and gas production industries if methods were developed to estimate the potential for cap rock to fracture.